


Symbiosis

by illwynd



Category: Norse Religion & Lore, Thor (Comics), Thor (Movies)
Genre: Alternate Universe, Halloween, Inspired by Venom (Movie 2018), M/M
Language: English
Status: Completed
Published: 2018-10-31
Updated: 2018-10-31
Packaged: 2019-08-11 07:52:44
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 2,854
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16471700
Author URL: https://archiveofourown.org/users/illwynd/pseuds/illwynd
Summary: Thor and Loki, ancient Asgardian gods, secretly go to Midgard to enjoy the Halloween festivities.





	Symbiosis

**Author's Note:**

> The crop of spookyfics is small this year, but hopefully this will be a fun one. 
> 
> This is set in our world, not MCU. Clearly, I saw Venom last weekend.
> 
> Happy Halloween!

In the dark theater, there is the sound of crunching popcorn, and Thor leans close against his brother in the back row, watching the movie they had chosen.

It is Halloween weekend on Midgard, and they both learned years ago how much they enjoy this mortal holiday. Loki is pleased by the costuming and the chaos and the upsetting of the everyday order; he first mentioned it several decades ago, returning one day to Asgard and telling Thor excitedly how the mortals thrill each other with tales of death and dread, and dress up to pretend to be other than they are and glimpse just for one night possibilities they would shun on any other day.

“Oh,” he added, “and also there is candy.”

Thor had agreed to visit the mortal realm to see the celebration for himself the following year, and he found that it delighted him as well.

“It is much like the way they think of storms,” he mused after he had seen it. “The parts of nature that they find frightening, and how they tame the idea.”

So they had agreed to enjoy those holidays together. To journey down to Midgard and wander streets lit with gourd-carved candle lanterns, to breathe crisp air and kick fallen leaves and grin at mortal children’s antics. Sometimes it amused Loki most to have them don flimsy fabric costumes, pretend to be demons or ghouls or creatures. Sometimes they went as themselves, in some older form, terrible to mortal eyes—only on this night would they be seen and garner barely a glance, the flickers of lightning under Thor’s skin dismissed as mere pyrotechnics, the horns on Loki’s brow getting a nod of praise for his skill in makeup.

Even as the mortal realm advanced further over the years, as their celebrations turned more toward the safe and sterile and confined, Thor and his brother still enjoyed those nights.

The mortals’ stories, in particular, grew yet more vivid.

Many years Thor and Loki find the most gruesome, dreadful film in the theaters to take in at the end of their evening, munching warm, greasy popcorn from the concession stand, and milk duds and peanut butter cups smuggled in from their candy haul, together watching the pouring blood and the transformations, listening to the screams and the high short notes of a plaintive violin as it foretells some character’s impending doom.

This year, they stand outside the theater for some minutes trying to decide.

“But we saw the original,” Thor argues.

“Yes, and all the less reason for us to view the remake, then, no?” Loki replies, with a shrug, as he peers at the row of movie posters, little flickering bulbs all around them in the darkness. “Let us have a new tale.”

“Which one would you choose?”

In the end, Thor gives in and lets Loki have his way. Surely this film will be enjoyable as well, and—

At first Thor is disappointed. It seems hardly even to be _attempting_ to frighten; the symbiotes have a certain eerie mystery about them, and the way their human hosts move is mildly disturbing to view, but then each time there soon comes a moment of ridiculousness that leaves him laughing instead.

Still, the popcorn swiftly disappears from the bucket, and the pile of candy wrappers crinkles in the bag, and Thor cannot claim he is not entertained.

He glances over to Loki.

They always pick the back row, and they always hope for the theater to be mostly empty, for if the film loses their interest they will still have the thrill of each other, of forbidden things done in what is technically something of a public space.

It looks like this time, though, the film is engrossing enough that he will not soon have his brother’s hand down his trousers, his strokes timed so that Thor must choke back his moans when the noise of the movie is quietest.

Instead he spends a moment gazing at his brother’s lovely profile in the dark, eyes bright on the screen, watching intently.

As Thor attends to the movie further, he becomes gladder and gladder of Loki’s choice, as he finds himself warming to the story in ways he did not expect, and halfway through, he has completely different ideas in mind.

Thor’s eyes are wide, and what he thinks cannot be what they meant—but no, this _is_ purposeful, the filmmakers did _not_ intend to make their merging horrifying, as it could have been. The character, Eddie—there is sweat on his skin and a wild look in his eye as the symbiote engulfs him. He tenses at the sound of Venom’s voice coming from within his own mind, but it is not the tension of fear. Of confusion at first, of alarm, dismay, but then it is merely _attention_.

The symbiote is Eddie’s lover, and Eddie has his lover _inside_ him, part of him in a way no other could ever be.

Thor squirms a little in his seat and reaches for his brother’s hand.

“Eww, Thor, you have popcorn butter all over your fingers,” Loki whispers, slithering out of his grasp.

Thor hastily wipes it off but he is soon swept up in the film anyway and does not dare try again.

An hour later, they stroll out of the theater together, and Thor is practically vibrating with delayed desire. The thought he’d had, and which is now consuming his mind. They wander a bit, taking in the night’s aura, the high clouds skittering past a gibbous moon, the rustle of wind in leaves, the occasional distant screech of tires as teenagers engage in mischief.

Loki is smiling to himself, gazing off into the darkness. “So what did you think of it, in the end? Still wish we had gone to see _Halloween_ instead?”

“No,” Thor admits. “I… enjoyed this film. Very much.”

Loki nods. “There were a few visual choices that I can’t help questioning, at least if we were meant to take it seriously... I mean, _that tongue_... But the characters were charming.”

Thor licks his own lips.

He had not even _thought_ about the tongue, as shocking as that may be.

They walk in silence for a few minutes more, until Loki’s arm slides around Thor’s middle. “I can hear you thinking, brother. What’s on your mind?”

Thor struggles for words. Tries to gather up his courage, because Loki may very well laugh at him and mock him for this eternally. _Thor, do you remember that film? You know, the one where afterward you decided you wanted…_ Thor’s heart thumps and he breathes with some difficulty. Skin prickling with dread worse than during any horror movie they have ever seen.

“What I enjoyed most was… the notion of such a symbiote. Of being bonded with it, sharing a body,” Thor says at last, and he is careful to keep his voice level and not meet his brother’s gaze so it will not be quite so obvious how nervous he is. His brother always picks up on such things and tugs at them like a loose thread.

“Oh?” Loki says, and Thor cannot tell whether it is a sound of polite interest or if he is genuinely intrigued. But he gives Thor nothing to take hold of, so all he can do next is take the plunge.

“Do you… do you think it would be beyond the limits of your shapeshifting abilities?”

They keep walking, their steps do not falter even on the cracks of the sidewalk, Loki’s arm remains around him, but Loki makes no reply for far too long. And when he does answer, his voice is brittle.

“I cannot imagine what you might be asking of me. You don’t think highly of shapeshifting of that sort. You know that. It’s _deceitful_ and it makes of me a snake.”

Now Thor can feel the tension in Loki’s arm against the small of his back, and he swallows heavily.

It has been hundreds of years. And they have been doing better, such that most days Thor need not even think of those times. They have been mending their relationship, doing things like these visits to Midgard for pleasant holidays together. Risking their secret intimacy, which no one else knows, because it makes them both happy, fills some emptiness in their lives. And the last time they both truly experienced that emptiness…

“I don’t think that,” Thor answers. “And your skill in it is great, more than I can comprehend. I admire it, and it frightens me. Frightens me in the good way.”

The tension in Loki’s arm softens—Thor had been unsure, uncertain that even this admission could mollify his brother, uncertain whether this misstep had ruined things beyond repair—and Thor sighs his relief.

Then the tension softens even more and Thor realizes that isn’t what is happening at all. The shadow of his brother is gone from the corner of his eye and instead Thor feels something moving against his back, beneath his clothes, upon his skin. Spreading, oozing, and—

It is somehow all at once _beneath_ his skin, _inside_ him, and Thor stumbles. They had been in the middle of a city park, tall trees and damp grass and iron benches, and Thor strays from the path, gasping as the strange sensation takes hold of him.

He bumps up against the trunk of a huge oak, leans his shoulder against it.

“Loki,” Thor whimpers.

His brother’s voice comes back to him from inside his own head, and it is not the low roar of the symbiote in the movie, it is only Loki’s voice, but it _resonates_ so that he feels it in every cell of his body.

_Yes?_

Thor sighs so deep it is practically a moan.

_Is this what you desired, Thor?_

And yes, oh yes, it is. It is within him, and it is his brother. One flesh, as if they were indeed born of the same mother, as they had once believed. It is having Loki so close to him, so close they could not ever be torn apart. If they could live like this, in the same body, Thor would never have to fear, nor feel alone, nor dread that some mere mistake or some ancient lie or something else he cannot know or foresee will once again change everything. Will make his brother hate him. Will make him nearly come to hate his brother as well.

This is exactly what Thor has always desired, being able to hold inside himself the one he loves most dearly.

The knowledge pulses in his veins, throbbing hot as fire.

And more than the knowledge, the _sensation_ —the sensation ripples through him, and all Thor can do is shiver and breathe and try to stay on his feet. He recalls the way the character in the film had looked, like half a wreck at all times, like a walking disaster, and he writhes in sudden sympathy.

_Really, Thor? You wished to have a monster from another world within you?_

Thor can feel the symbiote—his brother, his lover—moving inside him, all through his belly, up his chest, down his legs. Almost painful, but on the other hand it is on the brink of overwhelming, and Thor loves it.

“You have never been a monster to me.”

_Ah, but you cannot deny that is just what I am. An amoral creature, murderous and threatening at any moment to kill you as well, the only one who tolerates it._

“You are my brother,” Thor says. “And I do not ever want to be parted from you again.”

But Loki’s voice goes on, as if he had not heard.

_Or perhaps merely controlling you? Making you do as I wish, for reasons you cannot comprehend._

“No,” Thor whispers. “It’s _we_ , Loki. It’s always been us together.”

With a silent snarl the symbiote moves, expands in a way that _is_ painful, and Thor cannot stop himself from crying out, his body jerking.

_You asked for this. You willingly make yourself vulnerable to me in a way you cannot possibly fight, if I were to choose to use it against you. I could tear you apart from the inside._

Tears spring up in Thor’s eyes—from the shock of pain, from the agony. He can barely speak. Barely mumble. If Loki were not inside him, in his head, he would not think he would be heard.

“If you do... I will still be willing.”

Three heartbeats pass. Then the pain fades, and Thor feels the symbiote pulling back as well, and he almost protests at the loss before he realizes his brother is not leaving him.

Instead the symbiote is engulfing him; Thor feels it as the ooze covers more and more of his skin, and he can only for a brief moment hope that there are no mortals thinking to cut through this park at this hour on Halloween night, lest they see _this_. Whatever this looks like from the outside.

From the inside, it is oddly warm, and oddly constricting, like truly being within another’s body. There are waves of motion, like muscles tightening, squeezing with him inside. He feels he _could_ not choose to move by his own will; his limbs are only the structure for another being to use.

But that is not what it is. He is not being _used_. He is instead being loved.

And though the symbiote squeezes along the large muscles of his chest, his shoulders, his thighs, it pays special attention to smaller, tender parts of his flesh.

Thor feels it perfectly enclosing his cock, fitting to him tight and wonderful. And he feels it sheathing itself inside him, filling him full from behind, so smoothly and subtly it is like it always belongs there.

It feels nothing like the way Loki’s cock feels in their more ordinary activities, but Thor has no doubt that it _is_. And it moves all around him in a slow wave of clench and release, slow warm oceanic strokes upon his every nerve inside and out, and Thor can do nothing but let it all happen.

It fills him so deep he is sure there is no separation between them, no place where Loki ends and he begins. It fills him so deep he feels it swelling in his abdomen, squeezed again by the symbiote that encloses him.

He cannot speak; he merely _feels_ , feels his brother within him and around him and giving him this, and he has never felt such sharp, aching joy.

When the rising pleasure crests and he cries out, the symbiote muffles the sound by covering his face, entering into his mouth as well, and it feels just like the deepest kiss. Inside him, below, it swells in little pulses and the part holding his cock constricts and he wonders if his semen will mingle with it, if Loki will perhaps keep Thor’s seed inside himself when he returns to his own form, and that thought sends renewed shivers through Thor’s body.

Loki continues to hold him like that afterward until he comes back to himself, recovers his strength and his balance. Receding, pulling out of Thor’s body, coalescing into his usual form beside him.

Thor still feels debauched, reeling from the intensity of his orgasm, and he wonders if it is obvious from his appearance. If he looks as ruined as the character had on the screen.

By contrast Loki seems put together, but it is there in his eyes, a wild look, and he kisses Thor with his own mouth instead, ferocious until finally he calms.

“These Midgardians have the strangest ideas,” Loki says as he pushes Thor against the oak tree, winding his arms around him and hooking his chin onto Thor’s shoulder so he can use Thor for his support, for a place to rest against.

Thor welcomes it, holding Loki there in turn.

If anyone were to stumble across them now, they would be thought merely two amorous young men being slightly naughty in the nighttime park, enjoying the little thrill of danger. No one would ever suppose them to be two ancient gods, two brothers, struggling to heal old wounds between them.

“Thank you for indulging me,” Thor murmurs into Loki’s hair, loving him as hard as he can.

“Though I suppose really it’s strangest that it took so long for them to find monsters to be appealing mates, rather than things to flee or kill,” Loki muses back, as if he had not heard. “They are such bizarre creatures themselves, after all.”

“Yes,” Thor agrees, warm inside though the evening is turning cool, the air tasting of clouds. “They are.”

After a few more minutes, he hears Loki chuckling to himself.

“They said it right there in the film. _Up his ass,”_ Loki quotes. “Blatant. Not bothering to conceal it at all.”

Thor laughs with him, feels Loki’s smirk against his neck.

A few minutes later they finally pull apart, though they still clasp each other’s hand, and like that they head home.


End file.
